Deer, elk birth rates in Aspen area concern wildlife officers
Deer and elk caught a break this winter and they need it, according to officers with Colorado Parks and Wildlife.
The warm weather, lack of snowfall and disappearing snowpack at lower and midlevel elevations have made it easier for deer and elk to find food, said Kevin Wright, district wildlife manager for the Aspen area.
The animals also are more dispersed than normal, so they are less susceptible to disease and disturbance from humans and their dogs, he said.
But Colorado Parks and Wildlife officials remain concerned about the low fawn-to-doe ratios in deer and calf-to-cow ratios in elk in the Aspen and Glenwood Springs area. Wright and other wildlife officers working in the Roaring Fork Valley performed their annual aerial survey in late December and early January. They fly by helicopter over winter ranges to take representative samples of the ungulates.
They found a ratio of 32 calves per 100 cows in Game Management Unit 43, which covers the south side of Highway 82 from Glenwood Springs to Castle Creek Valley south of Aspen and the Crystal Valley.
The ratio was 35 calves per 100 cows in Game Management Unit 47 on the north side of the Roaring Fork Valley and up to Independence Pass.
The ratios have stalled in the low and middle 30s for at least 10 years, Wright said.
“To me, that’s an indication that something’s wrong,” he said. The factors could include disturbance of deer and elk by people and their dogs during tough winter months when the animals need to reserve their energy to survive, according to Wright. The habitat also is shrinking due to development and winter-range forage is often decadent and in poor condition because of lack of fire in the ecosystem.
The birth rates are enough to maintain the elk herd, but it’s not a “healthy number,” Wright said. Colorado Parks and Wildlife wants to see ratios for elk between 48 and 52 calves per 100 cows, he said.
Colorado wildlife officials have been concerned for years over the plummeting deer herd populations. Disease, habitat issues and tough winters have decreased deer populations in Colorado. Deer typically cannot survive winters as well as elk.
The snowpacked winter of 2007-08 “hit us hard,” Wright said.
This winter — where the weather turned mild after a cold and snowy start — could give the numbers at least a temporary boost, according to Perry Will, area wildlife manager for Area 8, which includes Aspen. His rule of thumb is if there is “brown ground” at Christmas, deer generally do well. He noted that there was deep snow during the holidays, so he was getting concerned. That concern dried up in January along with the weather.
Wright said the aerial survey showed a ratio of 48 fawns per 100 does on the south side of the Roaring Fork basin and 53 on the north side. Wildlife officials would like to see ratios in the 70s per 100 does, he said.
Colorado Parks and Wildlife creates models of deer and elk populations in March based on the observed numbers in the field. The models consider factors such as mortality rates to estimate populations and trends. Those are used to determine how many hunting tags will be issued.
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Spend enough time on the trails and slopes of Snowmass Village and you’ll probably see Brandon Hawksley at some point — or his handiwork, anyway.